1. Field of the Invention
The present invention relates to an image forming device used in, for example, a copier, a printer, a plotter, or a fascimile machine for producing toner images on a recording medium.
2. Description of the Related Art
U.S. Pat. No. 3,689,935 describes a conventional image forming device including a multilayered particle modulator (or aperture electrode), a potential application means, a toner supply means, and a recording medium positioning means. The particle modulator comprises a layer of insulating material, a continuous layer of conductive material (forming a shield electrode) coated on one side of the insulating layer, and a segmented layer of conductive material (forming control electrodes) coated on the other side of the insulating layer. Each segment of the segmented layer is insulatively isolated from each other segment in the layer. At least one row of apertures is formed through the multilayered modulator so that a segment of the segmented conductive layer surrounds each aperture. The control electrodes control according to an image signal applied thereto a flow of toner particles to form a toner image on a recording medium. The potential application means selectively applies a potential between the control electrodes and the shield electrode. The toner supply means supplies toner particles charged so that their flow through the apertures is controlled by the potential applied to the control electrodes. The recording medium positioning means moves the recording medium relative to the aperture electrode and into the path of the toner particle flow.
Japanese Patent Publication Kohyo HEI-1-503221 describes obtaining an image on a recording medium by controlling passage of toner using a matrix of electrodes.
However, there has been known a problem with these conventional image forming devices in that the portion through which toner controlledly passes, i.e., apertures in the case of the aperture electrode and holes in the mesh of the matrix in the case of the aperture matrix, is difficult to form. Also, quality of the toner image can suffer when the toner builds up in the middle of the apertures or mesh holes over a long period of use, so that control of the toner is obstructed. Quality of the image can also suffer when the toner builds up enough to clog the apertures or mesh holes.